Display consoles adapted for plotting graphic images form images from an orderly matrix of points or pixels spaced regularly apart on the surface of the screen and whose pigmentation is determined as a function of the drawing or the graph which is to be made. This matrix is generally orthogonal and is formed by M.times.N pixels or points placed on the surface of the screen of the console at the intersections of M rows and N lines. The product M.times.N represents the total number of pixels or points visible on the screen of the console, on which the performance of the processor depends. In known constructions, the formats used go from dot matrices of 512 by 512 to 1024 by 1024 dots or pixels. These images are represented on the display controls or on the black and white or color television monitors by means of a "column-line" scanning system.
The line and frame television scanning method is appreciated in these devices for the numerous advantages which it offers, However, the sampled structure of the graphic memory which is interposed between the display console and the processor causes characteristic faults generally called "aliasing defects" which appear in the form of indentations or steps visible on the oblique portions and curved portions of the plots obtained on the screens when the image is fixed, or by the sudden disappearance or appearance of detail due to a slight movement of the image. These defects are mainly due to sampling the signal at discrete points of the image memory interposed between the screen of the console and the processor.
In high performance graphic equipment, these defects are corrected by different techniques consisting, for example, in increasing the definition of the displayed image or in increasing the capacity of the graphic memory by correlatively grouping together each pixel or point scanned with its neighboring points, or in compensating for the position rounded portions of the plot by varying the tint of the pixel surrounding the plot or else by carrying out treatments during reading of the graphic memory consisting in performing filtering and interpolation calculations on the signals read out from the graphic memory. In fact, the processors which consist in increasing the definitions of the displayed image tend to be replaced by filtering and interpolation processing processors which seem to be much more efficient and less costly. These processing methods have however the drawback of occupying much of the computing cycle time of the graphic processors, which makes these plotting methods relatively slow. For increasing the plotting rates, cabled logic circuits are used for replacing the software of graphic processors but these logic circuits have the drawback of being expensive and further requiring, for obtaining satisfactory corrections,intermediate processing by using for example cache memories, this processing being carried out at high speed and with high definition by exchanging data between the cache memory and the processor before the results are written into the graphic memory.